Through design meeting requirements

Vulcanization is a chemical process where sulfur or other materials form crosslinks in the elastomer and thereby improve the polymer s mechanical properties. In many instances, not all of the desired properties reach an optimum level simultaneously. The task is to achieve a balance of the most important property requirements through design of the cure system and time-temperature cure cycle so as to attain the necessary compound mechanical properties. Frequently, the curing equipment available, such as presses or autoclaves, do not allow the curing conditions to be varied as desired, and so a cure system compatible with the existing equipment must be designed and also meet the compoimd performance requirements. 

NOTE - 2 A device does not have an SIL, since SIL is a quantitative measure of the performance of the overall SIF. lEC 61508 expands the use of the SIL terminology to device design requirements documented in lEC 61508-2 and lEC 61508-3. Therefore, a SIL 3 device means that the device has either completed an evaluation that the device design meets the requirements of lEC 61508-2 and lEC 61508-3 to the SIL 3 requirements and/or has been analyzed to these same requirements through prior use or lEC 61508 Compliance assessments. Since a SIL claim limit can be achieved through different methods and may have many restrictions for use, always ask the manufecturer of a device how the claim limit was achieved and any restrictions for use that may apply. 

Operation of a traversing sampler for gravity flow of material for through-stream sampling is required to meet the following design factors ... 

For more than one capacitor bank one RVT for each bank will be necessary for the correct discharge of each bank, (Figure 26.5). An RVT, if provided with an additional star-connected tertiary winding rated for 110 V line to line, can aiso check the discharge condition and its duration and if it meets the design requirements. This can even be monitored remotely through a relay and control panel. 

It should be emphasized at this point that the speed of response is cnti-cal. The pressure transient pressure should not fall to less than 50% of the difference in pressure between the standby pump start pressure and the low oil pressure trip pressure. This is normally achievable with good design practice and the use of a switch and direct wiring. There is some tendency to use a transmitter and control through a remote computer. The latter arrangement is difficult to check on a shop test and normally is too slow to meet the requirement. An accumulator can be added and must be used if the requirement cannot be met. This additional hardware contributes to higher initial cost and possible reliability problems in the future. The direct switch method is therefore highly recommended. 

Scotch marine boilers (SM boilers) derive their name from the Scottish shipyards that built marine vessels for the British Navy. They were the first design of FT boiler to incorporate both furnace tubes and fire tubes inside the shell and replaced the brick-set boilers that used to burn through the bottoms of ships. The SM boiler was a particularly versatile design and quickly became the boiler of choice for many stationary (land) applications as well as for marine duty. Land-based SM boilers (now commonly called Scotch boilers) were not simply marine boilers adapted for stationary duty but incorporated specific design modifications to meet the requirements of land-based industry. 

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